Resistor structure for oil circuit breaker interrupter

ABSTRACT

A NON-INDUCTIVE RESISTOR STRUCTURE FOR THE PARALLEL RESISTOR IN AN OIL CIRCUIT BREAKER IN WHICH INDIVIDUAL RESISTOR COIL LAYERS ARE WOUND ABOVE ONE ANOTHER AND ARE CLAMPED TOGETHER BY A CENTRAL INSULATION ROD. EACH COIL LAYER IS DISPOSED BETWEEN SPACER PLATES WHICH ARE SLOTTED TO PERMIT PASSAGE OF A CONTINUOUS RESISTANCE WIRE FROM COIL TO COIL WITH ADJACENT WIRE COIL LAYERS BEING WOUND IN OPPOSITE DIRECTIONS.

Feb. 2, 1971 B RlETz ET AL RESISTOR STRUCTURE FOR OIL CIRCUIT BREAKERINTERRUPTER 4 Sheets-Sheet 1 Original Fi l ed March 12. 1965 7 2 7604MF3. KWK I. r

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' g-1 71 BRRIETZ ET sIsToR S RUcTiJRR FOR FOIL CIRCUIT BREAKERINTERRUPTER 4' Shets-Sheet 4 ori inal F'ile d March 12, 1955 UnitedStates Patent US. Cl. 338-62 3 Claims ABSTRACT OF THE DISCLOSURE Anon-inductive resistor structure for the parallel resistor in an oilcircuit breaker in which individual resistor coil layers are wound aboveone another and are clamped together by a central insulation rod. Eachcoil layer is disposed between spacer plates which are slotted to permitpassage of a continuous resistance wire from coil to coil with adjacentwire coil layers being wound in opposite directions.

This application is a division of copending application Ser. No.439,304, filed Mar. 12, 1965, now UJS. Pat. 3,392,248, in the name of-Earl B. Rietz et al., entitled Interrupter Structure Having ContouredArc Splitter Plates and Separately Housed Resistor Contacts and ResistorStructure Therefor, and assigned to the assignee of the presentinvention.

This invention relates to oil circuit breakers, and more specificallyrelates to a resistor which is to be connected in parallel with theinterrupter structure of an oil circuit breaker.

The object of this invention is to provide an improved resistorstructure for use with circuit interrupters.

Another important object of this invention is to provide a novelarrangement for these resistors wherein resistor coil layers are woundabove one another and are clamped together by a central insulation rod.

Another object of this invention is to provide a novel pancake resistorarrangement which provides easily accessible electrical connections ateach end thereof.

A further object of this invention is to provide a novel structuralarrangement for a pancake resistor which permits heat expansion of theunit and prevents free entrance of carbon into the unit.

A still further object of this invention is to provide a novel pancakeresistor structure which may be easily assembled.

In the performance of resistors for interrupter structures, it ispreferable to use a non-inductive resistor. Such resistors are commonlyformed by winding the layers of resistance wire in alternate directions.

It is a further important object of this invention to provide a novelstructure for permitting the simplified manufacture of a non-inductiveresistor having layers of resistance wire wound in alternate directions.

A further object of this invention is to provide a novel non-inductiveresistance structure.

These and other objects of this invention will become apparent from thefollowing description when taken in connection with the drawings, inwhich:

FIG. 1 shows a top plan view of an interrupter structure and the housingfor its parallel connected resistor.

FIG. 2 is a cross-sectional view, similar to FIG. 1, and illustrates theconnection of the resistor to the interrupter.

FIG. 3 is a cross-sectional view of FIG. 2 taken across the lines 3--3in FIG. 2, and particularly illustrates a novel resistor mountingstructure of the invention.

FIG. 4 is a side view of the resistor structure to illustrate the mannerin which the resistor wire is noninductively wound.

FIG. 5 is a plan view of the resistor of FIG. 4 seen from the left-handside.

FIG. 6 is a plan view of the resistor of FIG. 4 seen from the right-handside.

FIG. 7 is an exploded perspective view schematically illustrating themanner in which the plates permit simple non-inductive winding of theresistance wire.

FIG. 8 schematically illustrates the winding of the first layer ofresistance wire.

FIG. 9 schematically illustrates the winding of the second layer ofresistance wire.

FIG. 10 schematically illustrates the winding of the third layer ofresistance wire.

FIG. 11 schematically illustrates the winding of a fourth layer ofresistance wire.

FIG. 12 shows various elements a to r in the order in which they arestacked for the novel resistor structure.

Referring first to FIGS. 1 and 2, the novel resistor is shown with aninterrupting chamber structure.

As shown in FIGS. 1 and 2, the complete structure will be supported froman upper conductive casting 30 which can be suitably secured to the endof an electrical bushing. This electrical bushing extends through themain support tank (not shown) which contains oil in which the completeinterrupter structure is immersed.

The interrupter includes an insulation casing 31 which is suitablyconnected to the casting 30.

FIGS. 1, 2 and 3 additionally show a novel resistor structure which canbe used as the parallel connected impedance member for an interrupter.More specifically, a resistor structure generally shown by numeral inFIG. 1 is suitably secured to the interrupter structure of FIG. 1 withthe upper terminal of the resistor connected to member 30, and the lowerterminal of the resistor connected to the resistor contacts 151 and 152in the interrupter unit.

This resistor structure is formed in the novel manner particularly shownin FIG. 3, and includes a stack of resistor elements 181, which will bedescribed more fully hereinafter, which are contained within aninsulation tube 182. The tube 182 receives a plate 183 which may bemetallic which is prevented from moving upwardly by means of a splitinterference ring 184 contained in a suitable groove in casing 182. Anupper conductive housing or support 185 is then connected to plate 183by suitable screws such as screws 186 and 187 (FIGS. 1 and 3). The upperhousing section 185 has an upwardly extending flange section 18711(FIGS. 1 and 3) which receives bolts such as bolts 1 88 which serve tobolt the support member 185 directly to suitable portions of uppermember 30 of the interrupter structure.

The lower portion of the resistor structure of FIG. 3 includes a lowerplate 189 which bears against the bottom of the resistor stack 181 andwhich is prevented from moving out of the tube by a suitable splitinterference ring 190. The bottom of casing 182 is then received by asuitable conductive support 191 which, as best shown in FIG. 2, issecured to the bottom of the interrupter housing by screws 160 and 162which further serve to electrically engage the resistor contacts 151 and152.

In order to hold the resistor stack 181 together during assembly, awooden rod or other suitable insulation rod 200 extends through thecomplete resistor housing and is terminated at either end by nuts 201and 202 respectively. The plate 189 then seats atop a spring 203 whichexternally surrounds the lower end of rod 200 and its lower nut 202. Atthe upper portion of the structure, a pressure plate 204 bears atopstack 181 and receives a compression spring 205 which has its other endin engagement with the plate 206 which is carried within a suitableaperture in upper housing portion 185.

This novel structural arrangement permits the rod 200 to be in tensiononly during assembly of the device and removes any support function fromthe rod 200. The complete support for the resistor structure comes fromthe casing 182 and its upper and lower supports 185 and 191.

In order to assemble this novel structure, the resistor pack 181 isfirst inserted into the tube 182; the plate 183 and its interferencering 184 and the support 185 having been previously assembled in a loosemanner by the screws 186 and 187. This permits the lower splitinterference ring 190 to be inserted into tube 182. The screws such asscrew 186 are then tightened, which pulls the support 185 downwardly andinto engagement with the upper end of tube 182. At the same time, spring205 is compressed, and forces the resistor stack 181 downwardly untilplate 189 engages interference ring 190'.

Accordingly, the structural mounting, as indicated previously,completely relieves the wooden insulating rod 200 from the strongmechanical forces, as would occur during a short circuit interruptionoperation.

The electrical circuit for the system partly extends from housing 191which is appropriately connected to the terminal 220 through plate 189and spring 203. Note that the terminal 220 could be connected to theresistor contacts 151 and 152 in any desired manner other than throughthe housing section 191.

The upper end of the resistor pack terminates in terminal 221 which, bymaking plate 204 of metallic material, is electrically connected throughspring 205 and metallic plate 206 to the metallic upper housing 185 andthence to the upper conductive housing 30* of the interrupter.

In order to permit oil circulation through the resistor structure,bottom slots such as slot 225 are provided in the lower plate 189 andthrough openings 226, 227 and 228. Note that the uppermost opening 228is so arranged in the side of upper housing 185 that carbon and othersimilar impurities floating in the circuit breaker oil will not easilysettle into the resistor structure.

The main purpose of nut 201 is to hold the resistor pack together whenit is removed from the tube 181. Thus, the complete resistor pack, alongwith plates 189, 204, 183 and 206, serve as a subassembly of theresistor structure.

It is to be particularly noted that prior art resistor devices utilizethe central rod 200 as the main structural member for carrying theresistor structure from the interrupter. Thus, the rod necessarilybecomes very large which, in turn, enlarges the complete unit.

The manner in which the resistor package 181 is formed is particularlyshown in FIGS. 4 to 11. The assembly of the resistor of FIGS. 4 to 11will be recognized as the resistor structure removed from its housing182 in FIG. 3. Note particularly that the spring 203 is captured bylower nut 202 by means of a square sheet 250 of FIGS. 4 and 5 whosecorners are folded over, as shown in FIG. 5, to capture spring 203.

It is extremely desirable that the resistor used as the parallelimpedance for the interrupter of the invention or of other similarinterrupter equipment be of a noninductive nature. Non-inductiveresistors are generally well known, and are formed by winding aresistance wire in several layers with alternate layers, for example,being wound in opposite directions. In this manner, the magnetic fieldsinduced in adjacent layers oppose one another so that the inductance ofthe coil is negligibly small.

Present arrangements for achieving the opposite winding direction foralternate layers of resistance wire are extremely awkward, timeconsuming, and the wire can- 4 not be wound directly from a wire spool.The novel resistor structure shown in FIGS. 4 to 11 is one in which anon-inductive resistor can be wound directly from a wire spool with thecoils or adjacent layers being suitably separated to keep creep voltagestress for between-layer cross-overs below a safe maximum value.

In accordance with the invention, each layer of resistance wire isassociated with a set of spacers and plates wherein the spacers andplates have suitable notches therein for permitting placement andwinding reversal of the resistor wire which is wound from a singlespool. Moreover, the spacers and plates for adjacent layers aredisplaced from one another which permits a similar displacement at thebetween-layer cross-over to keep voltage creep stresses to a minimum.

In FIGS. 4 and 8 to 11, there is illustrated the formation of the firstfour layers of the resistor, it being understood that the completeresistor will be formed in an identical manner.

Referring now to FIG. 4, there is shown four groups 260, 261, 262, and263 respectively of three plates and a winding plate each. The groups260 through 263 are shown in FIGS. 8 to 11 respectively. Each of thestacks 260 through 263 formed of plates, best shown in FIG. 7 for thecase of stacks 260 and 261 in exploded persective view.

The individual plates of stacks 260 through 263 are further shown inFIG. 12 as elements a to r, which are in the order in which the platesare stacked. Each of the plates are mounted on the square wooden shaft200. The group of plates 260 is shown in FIG. 12 as elements a, b, c andd, and includes winding plate 270, first and seccond slotted plates 271and 272, which are identical in construction and contain narrow slots273 and 274 respectively, and notches 276 and 277 respectively, and acentral plate 278 which contains a V-shaped notch 279.

Each of the remaining groups are made up of similar plates to thoseshown in FIG. 12, elements a, b, c and a, but are rotated clockwise by90 with respect to the plates of an adjacent group. This feature permitsapplicants novel displaced cross-over point in the resistance winding.

The method of winding the non-inductive resistor of the invention whenusing plates of the type shown in FIGS. 4 to 12 is best understood fromFIG. 7 for the case of the first two groups 260 and 261.

Referring particularly to FIG. 7, the resistance wire 290 is taken fromsome suitable spool, not shown. The various plates such as plates 271,278, 272 and 270 are then contained on the square wooden shaft 200 andthe resistance wire 290 is placed in the groove 276 of plate 271. Thiswire is then brought to the top of the sloping portion of V-shaped slot279 and then rides down to the slot at the bottom thereof. At thispoint, the wire extends over to the bottom of the narrow slot 274 andthence to the top surface of the winding plate or disk 270. The woodenshaft 200 is then rotated so that the resistance wire winds on plate 270in the direction shown by the arrow 291. Some predetermined number ofturns are then formed on the plate 270 to form a pancake-type resistancewinding 292.

The next group of plates 261 have been assembled and are rotated by 90with respect to the similar stack of plates 270. The end of pancakewinding 292 is taken from a point to the rear of the winding in FIG. 7,and is bent directly over into the notch 276a of plate 271a of group261.

In a manner identical to that for group 260, the wire then enters theV-shaped slot 279a of plate 278a to the bottom of the slot and then overthrough the bottom of slot 274a of plate 272a. Thereafter, the wire isplaced immediately on the winding surface of plate 270a and the assemblyis rotated in such a direction that a pancake resistance winding 294 isformed with the wire winding in the direction of the arrow 293. Notethat winding 294 is wound oppositely to winding 292, whereby themagnetic fields generated by each of the windings when current flowpasses therethrough are in opposing directions, thus rendering these twowinding sections relatively noninductive.

Clearly, this winding process continues until the end of the resistor isreached with the adjacent windings being wound oppositely from oneanother. Moreover, the points at which each of the windings terminatesand crosses over to the next group of plates are displaced with respectto one another by 90, thereby improving the voltage distribution acrossthe winding.

Although this invention has been described with respect to its preferredembodiments, many variations and modifications will now be obvious tothose skilled in the art, and it is preferred, therefore, that the scopeof the invention be limited not by the specific disclosure herein butonly by the appended claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. A non-inductive resistor comprising a plurality of spaced pancakewindings of a continuous resistance wire and a plurality of sets ofspacer plates between said windings; each of said sets of platesincluding a first plate having an off-center slot therein extending fromthe periphery thereof, a second plate having a notch in the peripherythereof, and a central plate interposed between said first and secondplates having a pie-shaped slot eX- tending from the periphery thereof;the bottom of said pie-shaped slot in said central plate being adjacentthe bottom of said off-center slot in said first plate; one side of thebeginning of said pie-shaped slot in said central plate being adjacentsaid notch in said second plate; said resistance wire extending acrosssaid notch, along one side of said pie-shaped notch and through thebottom of said off-center slot in passing from one pancake winding to anadjacent pancake Winding; adjacent pancake windings being wound inopposite directions.

2. The device substantially as set forth in claim 1 wherein saidoff-center slots of each of said sets of adjacent plates are rotatedwith respect to one another by a predetermined angle.

3. The device substantially as set forth in claim 1 wherein each of saidfirst and second plates include both said notch and said off-center slotwhereby said first and second plates are identical.

References Cited UNITED STATES PATENTS 2,355,477 8/1944 Stahl 338299UX2,844,692 7/1958 Berkelhamer 338-299X 2,937,355 5/1960 McNally 33862RODNEY D. BENNETT, JR., Primary Examiner T. H. TUBBESING, AssistantExaminer US. Cl. X.R. 338299, 305

